The present invention relates a torque transmission apparatus for an automobile.
There has been a torque transmission apparatus as shown in FIG. 24, for example, as a related torque transmission apparatus. FIG. 24 is a cross-sectional view illustrating a main part of the related torque transmission apparatus.
As shown in FIG. 24, the related torque transmission apparatus 301 is disposed in such a manner that an output shaft 305 can rotate relative to a crankshaft 303. A clutch pressure plate 307 is provided on the output shaft 305 as an integral part thereof, and a clutch housing 311 faces to the clutch pressure plate 307 via a clutch plate 309 in a direction extending along an axis of rotation.
A presser ring 315 is disposed adjacent to the clutch housing via a thrust bearing 313. The presser ring 315 engages with a casing 317 which is on a fixed side in a rotating direction and is designed to move in the direction along the axis of rotation. A support ring 319 faces to the presser ring 315.
A cam mechanism having a ball 321 is provided between the presser ring 315 and the support ring 319. The support ring 319 abuts with a support ring 325 supported on the casing 317 side via a thrust bearing 323.
A gear 329 provided on one end of a shaft 327 meshes with the support ring 319. A gear 331 is provided on the other end of the shaft 327 to mesh with a pinion 335 on a motor 333 side.
Consequently, the support ring 319 rotates via the pinion 335, the gear 331, the shaft 327 and the gear 329 by virtue of the driving of the motor 333. This support ring 319 rotates relative to the presser ring 315 and then, a cam mechanism having a ball 121 works to produce a thrust. This thrust so produced functions as a reaction force to the support ring 325 and moves the presser ring 315 to thereby press the clutch housing 311 in the direction along the axis of rotation.
The clutch housing 311 is moved by the pressing, and the clutch plate 309 is engaged between the pressure plate 307 and the clutch housing 311 so moved. A torque transmission from the crankshaft 303 to the output shaft 305 side via the clutch plate 309 is implemented by the engagement (for example, refer to JP-A-06-264978).
In the aforesaid construction, however, since the pressure plate 307, the clutch plate 309, the clutch housing 311, the presser ring 315, the cam mechanism having the ball 321 and the support ring 319 are disposed in series in the direction along the axis of rotation, it is difficult to make the torque transmission apparatus compact in the direction along the axis of rotation. In addition, as the friction radius of the clutch plate 309 increases, the torque transmission apparatus is forced to increase in size in a direction along a rotating radius. Thus, it has been difficult to make the increase in friction radius compatible with the suppression of increase in overall size of the apparatus.